Slip clutch with signal

ABSTRACT

A slip clutch with a signal for revealing when the clutch is slipping, and including a rotatable driving member and a rotatable driven member rotationally engaged with the driving member, and with the two members being rotatable relative to each other. A projection is carried on each of the two members, such that they hit against each other when the clutch is slipping, and one of the members is of a metallic material and cylindrically shaped so that it rings like a bell when its projection is being hit. A sphere is carried by the other member and is under the influence of centrifugal force to extend radially outwardly and hit the other member when the clutch is slipping and thereby create the audible signal.

United States Patent 1 Heth et al.

1 1 Sept. 4, 1973 1 SLIP CLUTCH WITH SIGNAL [73] Assignee: JacobsenManufacturing Company,

Racine, Wis.

22 Filed: May 15, 1972 21 App]. No.: 253,635

1,240,889 9/1917 Shepp 116/60 2,939,301 6/1960 Huddle 64/30 R FOREIGNPATENTS OR APPLICATIONS Netherlands 64/30 R Primary Examiner-Allan D.Herrmann Attorney-Arthur J. Hansmann [57] ABSTRACT A slip clutch with asignal for revealing when the clutch is slipping, and including arotatable driving member and a rotatable driven member rotationallyengaged with the driving member, and with the two members beingrotatable relative to each other. A projection is carried on each of thetwo members, such that they hit against each other when the clutch isslipping, and one of the members is of a metallic material andcylindrically shaped so that it rings like a bell when its projection isbeing hit. A sphere is carried by the other member and is under theinfluence of centrifugal force to extend radially outwardly and hit theother member when the clutch is slipping and thereby create the audiblesignal.

8 Claims, 6 Drawing Figures SLIP CLUTCH WITH SIGNAL This inventionrelates to a slip clutch with a signal for revealing when the clutch isslipping, and the signal is an audible signal which is similar to aringing bell.

BACKGROUND OF THE INVENTION Slip clutches are commonly known and widelyemployed in transmitting rotational drive from a driving member to adriven member. These clutches are arranged such that when the forcetransmitted between the members is of a pre-determined amount, then themembers no longer transmit a greater force, and they may even terminatetransmitting any force, as the two members slip relative to each otherand are no longer in full driving relationship. Further, prior art slipclutches commonly employ adjustable springs which permit the clutch tobe adjusted to vary the amount of maximum force which can be transmittedup to the point when the clutch slips.

However, one deficiency and one area of concern with regard to prior artslip clutches is that related to informing the user that the clutch isactually at its maximum force condition and that the clutch is thenslipping. Where a slip clutch does not have a signal to indicate that itis slipping, the clutch can be worn out or otherwise damaged by virtueof having the clutch continue to be subjected to its driving forcethough it is not operating in the manner which would permit it totransmit that force without slipping under conditions where two or moreparts of the clutch are in frictional contact with each other and arethus abrading each other. Further, the prior art clutches can bevisually observed to determine whether or not they are slipping, atleast under certain clutch arrangements and conditions of operation andinstallation. However, such observing of course requires the attentionof the operator, and this is undesirable in that he must then bedistracted from paying attention to other activities.

Accordingly, it is a general object of this invention to provide a slipclutch with a signal which will reveal when the clutch is slipping.

A more specific object of this invention is to provide a slip clutchwith an audible signal which will be detectable over the normal soundlevel of machinery operation, and which will also indicate the degree orspeed of clutch slipping action.

Still further, it is a specific object of this invention to accomplishthe aforementioned objectives and to overcome the aforementionedproblems and to do so with a clutch which is simple in its structure,easily manufactured and maintained, and with a clutch which is fullycapable of being installed in usual and conventional spaces and does notrequire special installation or a special large space or specialaccessories or additional equipment in the production of the signal andin the transmitting of the signal to the attention of the operator.

Still further, it is a specific object of this invention to provide asignal for a slip clutch, as mentioned above, and to do so with partsand an arrangement where the parts do not readily wear out and which donot damage each other though they are operationally related to eachother and thus come into contact with each other. Further, inaccomplishing this and other objects, the clutch and the parts thereofproducing the signal are inexpensive and uncomplicated and they aretherefore easily provided and are easily maintained and replaced, ifnecessary. Further, the signal itself does not require any power andtherefore the clutch can operate at its full capacity.

Other objects and advantages of this invention will become apparent uponreading the following disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a longitudinal sectionalview through a preferred embodiment of this invention.

FIG. 2 is an end elevational view of one of the members shown in FIG. 1.

FIG. 3 is a sectional view taken along the line 3-3 of FIG. 2.

FIG. 4 is an end elevational view of another of the members shown inFIG. 1.

FIG. 5 is a sectional view of a fragment of a part similar to that shownin FIG. 3, but showing another embodiment of that part.

FIG. 6 is a fragment of a view similar to FIG. 1, but showing anotherembodiment of this invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A shaft 10 has acircular plate 11 affixed thereto, such as by welding designated 12, andthe shaft terminates in a threaded end 13. A first member, generallydesignated 14, and a second member 15 are mounted on the shaft 10, andthese members are rotationally related to the shaft and to each other inmanners hereinafter described. Friction discs 16 are also rotatablymounted on the shaft 10, and these discs are cylindrical and are of afriction material and they present flat faces on the opposite ends ofthe disc 16 to frictionally en gage the respective members 14 and 15 andalso the piece 11, as shown in FIG. 1. A compression spring 17 ispiloted on the shaft 10 and is adjustable thereon by means of the nut 18movable along the shaft threaded end 13. Thus the spring 17 is in endcontact with nut 18, at one end of the spring, and the other end of thespring 17 is in end contact with the face 19 of the circular member 15.Thus the spring 17 forces the members 14 and 15 into frictional contactthrough the friction disc 16 which is disposed between the member 15 andthe hub portion 21 of the member 14.

With the arrangement described thus far, and with the shaft 10 beingdriven and thereby driving the member 15 through the keys 22interengaged between the shaft 10 and member 15, a sprocket 23 is driventhrough the friction disc 16. Thus, in that arrangement, the member 15is the driving member while the member 14 is the driven member, and itwill be understood that the member 14 has its hub 21 welded to thesprocket 23 by the weldment designated 24. Also, a bushing 26 rotatablysupports the member 14 on the shaft 10.

The member 14 also includes a bell-shaped portion 27 which is secured tothe hub 21 by the weldment designated 28. A dimple or indent 29 isincorporated in the portion 27, and FIGS. 2 and 3 show that the portion27 is cylindrically and circularly shaped, and FIG. 1 shows that thecylindrical portion extends spaced from but radially in the plane of themember 15. Thus, the member 15 supports a sphere 31 which is freelysupported on the member 15 through the cylindrical opening 32 which is apocket in the member 15, as seen in FIGS.

1 and 4. Thus the sphere 31 is in the same plane transverse to the axisof the shaft as is the location of the indent 29. Thus, the members 14and 15 have respective projections 29 and 31 which are disposed in thesame plane transverse to the axis of the shaft 10, and they are radiallydisposed relative to the axis of the shaft 10 to be in a position wherethe sphere 31 can hit the projection 29. Further, the portion 27 and thesphere 31 are preferably of metallic material such that when the twoprojections 29 and 31 hit against each other there is an audible signalin the nature of a ringing bell. Such hitting action occurs when theload on the clutch is of a predetermined amount or in excess thereof sothat the member 14 is retarded in its rotation but the member 15continues to rotate with the rotation of the shaft 10. Under thoseconditions, the sphere 31 is subjected to centrifugal force and isradially projected outwardly to be in the path of the projection 29 andthereby strike the projection 29. FIG. 2 shows that there may be aplurality of projections 29 spaced around the bell-shaped portion 27. Itwill therefore be understood that when the clutch commences to slip, theaudible signal is produced and the operator will be informed that theclutch is slipping. In fact, depending on the degree of slip, that iswhether or not there is any rotation to the member 14, the frequency ofthe sphere 31 striking the projections 29, and even the sound frequencycreated by the striking action can indicate the degree of slipping thatis occurring.

If the driving and driven relationship of the members 14 and 15 werereversed from that just described, then a spring, such as the spring 33could be disposed behind the sphere 31 to yieldingly urge the sphere 31outwardly and into the path of the then rotating bellshaped portion 27which would be the driving portion of the clutch.

FIG. 5 shows a slightly different arrangement for the projections on thebell-shaped portion 27, and] here the projection 34 is shown to extendto the outer edge of the member 27, rather than just be in the path ofthe sphere 31 as seen in FIG. 1. However, the operation and generalarrangement is otherwise the same as shown in the other views in thedrawings. Of course there are many installations where a slip clutch isemployed, and one such installation is in connection with the drive of alawnmower cutting reel, and the clutch in that instance would slip whenthe cutting reel would meet an object which would retard the rotation ofthe reel. At that time, the audible signal would be created because ofthe relative rotation between the members 14 and 15. It will be furtherapparent to one skilled in the art that the driving and driven membersof the slip clutch could have the movable projection, such as the sphere31, under the influence of a spring, such as the compression spring 33,and with the movable projection being movable parallel to the axis ofrotation and with the other projections being spaced to the side of themovable projection, rather than radially spaced apart but instead beingaxially spaced from the sphere 31. Such word description should beapparent to one skilled in the art in view of the preceding descriptionand the drawings, including that embodiment shown in FIG. 6 where theportion 15 is re-shaped to be as shown in the portion 36 in FIG. 6 forsupporting a sphere 37 in an opening 38 which is a pocket. A compressionspring 39 urges the sphere 37 axially of the rotatable member 10, andthe sphere is therefore disposed in the rotational path of theprojection 41 formed as a dimple on a washer-shaped plate 42 affixed tothe bell portion 27. Thus, the projections 37 and 41 are disposed forhitting each other when the clutch is slipping, and this creates theaudible signal.

What is claimed is:

1. A slip clutch with a signal for revealing when the clutch isslipping, comprising a rotatable driving member, a rotatable drivenmember rotationally engaged with said driving member until apre-determined driving force therebetween is reached and whereupon saiddriving member rotates relative to said driven member, each of saidmembers having an outer surface and with said surfaces being facedtoward each other and spaced from each other, a projection on saidsurface of one of said members and extending toward the other of saidsurfaces for traversing a path of rotation in the space between saidsurfaces and upon rotation of said one member, the other of said membershaving a pocket extending into its said surface and having a limitingmeans in the depth of said pocket, a projection member movably disposedin said pocket and being movable therein against said limiting means andbeing supported therein to extend partly from said pocket and into saidpath of rotation of said projection on said one member for striking saidprojection when said members are rotating relative to each other, andwith said projection member being related to said pocket to berestrained by said pocket for retracting from said projection uponstriking said projection in creating the audible signal.

2. The slip clutch as claimed in claim 1, and wherein said limitingmeans is a spring disposed in said pocket and beneath said projectionmember.

3. The slip clutch as claimed in claim 1, and wherein said projectionmember is spherically shaped member.

4. The slip clutch as claimed in claim 3, and wherein said limitingmeans is a spring disposed in said pocket and beneath said sphericallyshaped member.

5. The slip clutch as claimed in claim 1, wherein said one of saidmembers includes a cylindrically shaped portion and is of a metalliccharacteristic to produce a sound of a ringing bell when being struck bysaid projection member.

6. The slip clutch as claimed in claim 5, and wherein said projection onsaid one of said members is an indent in said cylindrically shapedportion, and said projection member on said other of said members is aspherically shaped member of a metallic characteristic.

7. A slip clutch with a signal for revealing when the clutch isslipping, comprising a rotatable driving member, a rotatable drivenmember rotationally engaged with said driving member until apre-determined driving force therebetween is reached and whereupon saiddriving member rotates relative to said driven member, a projection oneach of said members and disposed in the rotational paths of each otherand being relatively movable toward and away from each other to hit eachother during the relative rotation and to thereby create an audiblesignal, said projections being of metallic characteristic to produce abell-ringing sound when creating the signal, one of said members beingpartly bell-shaped and encircles a portion of the other of said members,said projection on the encircled one of said members being a spheremovably supported on the latter said member to be under the influence ofcentrifugal force for radially outward movement to hit the other one ofsaid projections.

8. The slip clutch as claimed in claim 7, wherein said projection onsaid one of said members is an indent in the bell shaped portionthereof.

is a w a

1. A slip clutch with a signal for revealing when the clutch isslipping, comprising a rotatable driving member, a rotatable driVenmember rotationally engaged with said driving member until apre-determined driving force therebetween is reached and whereupon saiddriving member rotates relative to said driven member, each of saidmembers having an outer surface and with said surfaces being facedtoward each other and spaced from each other, a projection on saidsurface of one of said members and extending toward the other of saidsurfaces for traversing a path of rotation in the space between saidsurfaces and upon rotation of said one member, the other of said membershaving a pocket extending into its said surface and having a limitingmeans in the depth of said pocket, a projection member movably disposedin said pocket and being movable therein against said limiting means andbeing supported therein to extend partly from said pocket and into saidpath of rotation of said projection on said one member for striking saidprojection when said members are rotating relative to each other, andwith said projection member being related to said pocket to berestrained by said pocket for retracting from said projection uponstriking said projection in creating the audible signal.
 2. The slipclutch as claimed in claim 1, and wherein said limiting means is aspring disposed in said pocket and beneath said projection member. 3.The slip clutch as claimed in claim 1, and wherein said projectionmember is spherically shaped member.
 4. The slip clutch as claimed inclaim 3, and wherein said limiting means is a spring disposed in saidpocket and beneath said spherically shaped member.
 5. The slip clutch asclaimed in claim 1, wherein said one of said members includes acylindrically shaped portion and is of a metallic characteristic toproduce a sound of a ringing bell when being struck by said projectionmember.
 6. The slip clutch as claimed in claim 5, and wherein saidprojection on said one of said members is an indent in saidcylindrically shaped portion, and said projection member on said otherof said members is a spherically shaped member of a metalliccharacteristic.
 7. A slip clutch with a signal for revealing when theclutch is slipping, comprising a rotatable driving member, a rotatabledriven member rotationally engaged with said driving member until apre-determined driving force therebetween is reached and whereupon saiddriving member rotates relative to said driven member, a projection oneach of said members and disposed in the rotational paths of each otherand being relatively movable toward and away from each other to hit eachother during the relative rotation and to thereby create an audiblesignal, said projections being of metallic characteristic to produce abell-ringing sound when creating the signal, one of said members beingpartly bell-shaped and encircles a portion of the other of said members,said projection on the encircled one of said members being a spheremovably supported on the latter said member to be under the influence ofcentrifugal force for radially outward movement to hit the other one ofsaid projections.
 8. The slip clutch as claimed in claim 7, wherein saidprojection on said one of said members is an indent in the bell shapedportion thereof.